1. Field of Invention
This invention relates to master-slave robotic systems such as those used for laparoscopic surgery and more particularly to prevention of operator control of the surgical tools when an alignment difference between the master and slave exceeds a threshold value.
2. Description of Related Art
In a robotic system that allows for clutching of an end effector wherein movement of the end effector in response to movement of a handle can be selectively interrupted by the clutch mechanism such that the handle can be moved and rotated while the position and rotation of the end effector is held stationary, there is a possibility that the orientation of the handle and the orientation of the end effector will come out of rotational alignment. Should this occur, the commanded end effector orientation can differ significantly from the handle orientation. When the alignment difference is large, movement of the slave instrument may not feel as though it is fundamentally linked to the motion of the master handle, from the user's perspective.